1. Field of the Invention
The present invention relates to a process for the formation of a dry etching mask used for the formation of a pattern much finer than determined by optical limits, and a process for the formation of a micropattern using that mask.
2. Explanation of the Prior Art
One of processes for the formation of finely patterned thin films (micropatterns), for instance, is typified by a dry etching process. According to this process, for instance, a thin film is formed on a substrate, a resist layer is formed on that thin film, and that resist layer is patterned by photolithography into a finely patterned resist mask. Then, while that resist is used as a dry etching mask, an exposed portion of the thin film is dry etched off, after which the resist is stripped off to obtain a finely patterned thin film.
The finely patterned thin films formed by such a dry etching process, for instance, are used for micro-components, micro-layer members, interconnection patterns or the like that constitute microdevices such as thin-film inductors, thin-film magnetic heads, semiconductor devices, sensors using thin films, and actuators using thin films.
In recent years, there have been growing demands toward making microdevices much finer and, with this, toward microprocessing techniques for achieving much narrower pattern widths. For activation light rays used for the formation of mask patterns, too, excimer laser light such as KrF, ArF, and F2 as well as short wavelength irradiation light such as electron radiation have been put to practical use or studied.
With prior art dry etching processes, however, it is still theoretically impossible to form a pattern thin film much finer than determined by optical limits, because a micropattern thin film is formed using as a dry etching mask a resist pattern obtained by the patterning of a resist layer with an optical method.
The situations being like such, the present invention has been made for the purpose of providing a process of forming a dry etching mask capable of forming a micropattern much finer than determined by optical limits. Another object of the invention is to provide a process of forming a micropattern using that mask.